Southern California Institute for Research and Education, Long Beach VA Healthcare System, Long Beach, CA 90822, USA.
Department of Dermatology, University of California Irvine, Irvine, CA 92697, USA.
Cells. 2021 Dec 22;11(1):13. doi: 10.3390/cells11010013.
Cytoskeleton organization and lysosome secretion play an essential role in osteoclastogenesis and bone resorption. The cytoplasmic dynein is a molecular motor complex that regulates microtubule dynamics and transportation of cargos/organelles, including lysosomes along the microtubules. LIS1, NDE1, and NDEL1 belong to an evolutionary conserved pathway that regulates dynein functions. Disruption of the cytoplasmic dynein complex and deletion of LIS1 in osteoclast precursors arrest osteoclastogenesis. Nonetheless, the role of NDE1 and NDEL1 in osteoclast biology remains elusive. In this study, we found that knocking-down Nde1 expression by lentiviral transduction of specific shRNAs markedly inhibited osteoclastogenesis by attenuating the proliferation, survival, and differentiation of osteoclast precursor cells suppression of signaling pathways downstream of M-CSF and RANKL as well as osteoclast differentiation transcription factor NFATc1. To dissect how NDEL1 regulates osteoclasts and bone homeostasis, we generated conditional knockout mice in myeloid osteoclast precursors () by crossing floxed mice with -Cre mice on C57BL/6J background. The mice developed normally. The µCT analysis of distal femurs and osteoclast differentiation and functional assays in cultures unveiled the similar bone mass in both trabecular and cortical bone compartments as well as intact osteoclastogenesis, cytoskeleton organization, and bone resorption in mice and cultures. Therefore, our results reveal a novel role of NDE1 in regulation of osteoclastogenesis and demonstrate that NDEL1 is dispensable for osteoclast differentiation and function.
细胞骨架组织和溶酶体分泌在破骨细胞生成和骨吸收中起着至关重要的作用。细胞质动力蛋白是一种分子马达复合物，可调节微管动力学和货物/细胞器的运输，包括沿着微管的溶酶体。LIS1、NDE1 和 NDEL1 属于调节动力蛋白功能的进化保守途径。破骨细胞前体中细胞质动力蛋白复合物的破坏和 LIS1 的缺失会阻止破骨细胞生成。尽管如此，NDE1 和 NDEL1 在破骨细胞生物学中的作用仍然难以捉摸。在这项研究中，我们发现通过特异性 shRNA 的慢病毒转导敲低 Nde1 表达显着抑制破骨细胞生成，通过减弱破骨细胞前体细胞的增殖、存活和分化，抑制 M-CSF 和 RANKL 下游信号通路以及破骨细胞分化转录因子 NFATc1。为了剖析 NDEL1 如何调节破骨细胞和骨稳态，我们通过在 C57BL/6J 背景下将 floxed 小鼠与 -Cre 小鼠杂交，在髓样破骨细胞前体中生成条件性敲除小鼠 ()。 小鼠正常发育。远端股骨的 µCT 分析以及培养物中的破骨细胞分化和功能测定揭示了 小鼠和培养物中骨小梁和皮质骨两部分的骨量相似，以及完整的破骨细胞生成、细胞骨架组织和骨吸收。因此，我们的结果揭示了 NDE1 在破骨细胞生成调节中的新作用，并证明了 NDEL1 对于破骨细胞分化和功能是可有可无的。
